India, Dec. 29 -- Delhi's air quality was in the 'severe' range on Monday as a thick layer of fog spread across the Indo-Gangetic plains, impacting both flight and rail operations. Visibility dipped to 50 metres at both Safdarjung and Palam, with dense fog recorded for close to six hours, the India Meteorological Department (IMD) said.

Over 150 flights were delayed at Delhi's Indira Gandhi International (IGI) airport till 8am as per the flight tracking website FlightRadar24, with another six cancelled. The situation is expected to worsen through the day due to cascading delays and cancellations - particularly at other impacted airports. Several trains were also running at a delay.

"At 2.30am, visibility fell to 50 metres at Palam and re...